In integrated circuit (IC) fabrications, a patterned photoresist layer is used to transfer a designed pattern having small feature sizes from a photomask to a wafer. The photoresist is light-sensitive and can be patterned by a photolithography process. Furthermore, the photoresist layer provides resistance to etch or ion implantation, which further requires a sufficient thickness. When IC technologies are continually progressing to smaller feature sizes, for example, down to 32 nanometers, 28 nanometers, 20 nanometers and below, the thickness is not scaled down accordingly because of the resistance requirement. Depth of focus sufficient enough to cover the thicker photoresist degrades the imaging resolution. Multiple-film photoresist is introduced to overcome the above challenge. However, while a variety of such multiple-film photoresists have been generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect.